Process of producing dies from powdered metallurgy



1946- L. H. ORIN 2,413,512

PROCESS OF PRODUCING DIES FROM POWDERED METALLURGY Filed March 24, 1943 A /0. INVENTOR (g LUU/SHMOR/N ATTORNEYS 47 4/ ZZBY Patented Dec. 31, 1946 PROCESS OF PRODUCING DIES FROM POWDERED METALLURGY Louis H. Morin, Bronx, N. Y., assignor of onehalf to Davis Marinsky, Bronx, N. Y.

Application March 24, 1943, Serial No. 480,289

This invention relates to the art of producing, or what might be better said to be re-producing or duplicating dies. More particularly, the invention relates to the re-production of dies used in the art of forming die castings.

In the construction of dies, and particularly dies having relatively small and complicated impressions or cavities, it has been a difiicult and expensive procedure to produce such dies, particularly when large numbers of the individual dies are required on numerous machines in caring for large production of the articles in question. One example of such extensive uses is the formation of links or scoops of separable fastener stringers as is later specifically described for illustrative purposes.

Many machines are employed in productions of this kind, and each machine requires its individual die. Furthermore, there is the question of establishing production of identical parts or members, and notwithstanding the accuracy employed in the normal process of duplicating dies, there is bound to be some slight differentials.

It is the purpose of my invention to effect simplicity and economy in the production of duplicate dies of the kind under consideration, while at the same time establishing a more accurate production of identical parts, notwithstanding the number of machine units employing individual dies for the production of the products. It will also appear that a great saving in time will be effected by my improved process.

It is a further object to take advantage of the art of powder metallurgy and to provide an improved process of making dies from powdered metal.

Other objects and advantages will hereinafter appear.

The invention will be defined in the claims and illustrated by the following description taken together with the accompanying drawing in which certain embodiments of the invention are disclosed, and in which the separate parts are designated by suitable reference characters in each of the views, and in which:

Fig. 1 is a diagrammatic cross sectional View through a pair of dies used in the formation of links or scoops on a stringer tape in forming separable fasteners.

Fig. 2 is a perspective view illustrating one link at the beaded edge of a tape, showing the result of a casting formed as indicated in Fig. 1.

Fig. 3 is a face view of one of the die parts shown in Fig. 1.

Fig. 4 is a section on the line 44 of Fig. 3.

2 Claims. (Cl. 76-107) 2 Fig. 5 is a section on the line 5-5 of Fig. 3. Fig. 6 is a sectional view diagrammatically illustrating the step of forminga die cast mold. Fig. 7 is a sectional detailed view of the trimmed mold detached.

Fig. 8 is a diagrammatic view illustrating the step of forming a die from the mold of Fig. 7,

by powder metallurgy process.

Fig. 9 is a sectional view, showing the resulting powdered metal die with the mold thereon, and

Fig. 10 hows the resulting powdered metal die after the sintering operation.

In describing oneadaptation of my invention, I will illustrate dies as employed in forming die cast links or scoops, such as indicated at H, Fig. 2 of the drawing, upon the beaded edge [2 of a stringer tape l3. These articles of manufacture are referred to as separable fasteners, and sometimes identified as zippers. The links or scoops II are arranged at spaced intervals along the beaded edge l2, and the number of scoops employed will define what is termed stringer lengths.

The links or scoops in the construction shown .are of what I term double action links or scoops,

that is to say, each side surface l4, I5 is of the same construction, having male coupling portions I6, female coupling portions l1, projecting knobs la in the recesses or portions l! adapted to engage apertures or recesses l9 in the portions l6.

At this time it is well to point out that in producing a product such as the link or scoop II where both sides are identical, then the two die halves employed for forming these die castings would be identical. However, there are many articles of manufacture which would have different contours at opposed surfaces which would necessitate the construction of independent die parts, that is to say, die parts in which the impression or cavity of one would be difierent from that of the other. For example, this would also be true in forming links or scoops which have been in common use, having a male part only of one side, and a female part only of the other side. Here, left and right die parts would be necessary.

In that the process which is later described will apply to the construction of both die parts of a complete die, it is essential to deal with the construction of one die part only.

In Figs. 1 to 5 inclusive is illustrated the dies employed for producing the links or scoops II. In Fig. 1, two similar the parts are indicated at 20, and are shown in abutting relationship to each other with a cast link ll formed in the cavity or 3 impression 2| of these die parts. The casting material enters the cavities or impressions through a gate passage 22 from an injection nozzle, a part of which is indicated at 23. At 24 is shown a core pin arranged on the parting line of the die parts 20, and which forms the aperture l9 in the resulting casting, link or scoop.

Considering Fig. 3 of the drawing it will appear that the surface of the die part has recesses 25 opening into the cavity 2| for the reception of the core pin 9. This surface also has recesses 26 for the reception of the beaded edge I 2 of the stringer tape l3. Bordering the cavity as well as the recesses 25, 26 are raised walls 21, 28 which define relatively sharp edges of contact between both die parts 20, and also firm engagement with the tape l3. The edges as at 28 are cut lower to provide the necessary clearance for the tape thickness. This construction insures the formation of castings having no flare of metal, and this is desirable particularly when the castings are formed upon a mounting tape.

It will also be apparent from Fig. 3 of the drawing that recesses 29 are employed to form the resulting knobs 8 on the finished casting. The surfaces 30 are milled from the face of the die part in forming the raised relatively thin boundary walls 21-28. It is the milling operations necessary to produce the surfaces 30 that materially complicate the formation of dies of the kind under consideration, particularly in the formation of small castings where in some instances the complete length of the casting is only small fractions of an inch, for example of an inch.

Having made what might be termed a master die, and having produced die castings therefrom, such as the castings II, and having found that these castings meet all specification requirements, re-productions of these master dies can be produced as more fully hereinafter set forth.

In one procedure I take a die part 20 and fixedly mount it on a suitable backing 3| to form what I will term a mold part in order to distinguish it from the die parts 20. It will be understood that the cavity or impression 2| of the die part 20 forms one part of the mold cavity, the other portion 32 of the mold cavity is formed by a tubular body 33 in which is a plunger 34.

The parting line of the two molds is indicated at 35, and on this parting line is a gate passage 36 into which casting material from a nozzle, partiallyshown at 31, is pressure injected into the mold 'in forming the resulting-die casting .38, which would represent a negative or male replica of the die part 20, and this casting I will define as a templet or pattern. In forming this die casting, difierent materials can be employed, for example, zinc alloys can be used, and where greater strength is required, silicon bronze can be employed.

As many of the templets or patterns as may be needed from time to time can be made and used for producing duplicate die parts 20 or for each part of the die Where the pairs of die parts are of different constructions.

One method of procedure will comprise brazing or otherwise securing the templet 38 to the -surfaceof;..a-plung'er 39, whichoperates in a suitable cylinder or housing 40, the contour of which will correspond generally to the peripheral contour of the templet 38. The housing 40 actually forms part of the mold in which the resulting powdered metal die 4| is formed. At 42 is shown an ejector plunger 42 which also forms part of pression surface of the primary die.

the resulting mold for producing the powdered metal die 4|. The procedure is generally as follows:

When the plunger 39 with the templet 38 thereon is in raised position a measured quantity of powdered metal is inserted in the chamber defined by the walls of the housing 40 and the ejector 42, then the plunger 39 including the templet 38 are moved downwardly in the bore of the 7 housing 40 under a high pressure, producing a substantially solid homogeneous mass of powdered metal which results in the die 4| The ejector plunger 42 is then operated to eject the casting 4| after the plunger 39 and templet 38 have been withdrawn from the housing or cylinder 40. The die 4| is then sintered and hardened in producing the final product, and where required, may be polished as is the customary procedure.

Instead of proceeding as above, the templet 38 may be unattached or freely detachable with respect to the plunger 39 and retained in contact with the die 4|, particularly when it is desirable to ship or handle the die 4| to any great extent prior to the sintering thereof. The die 4| including the templet 38 is then placed in a heater to sinter the die 4|. The lower melting point of the templet 38 will result in the melting of this templet, leaving the resulting sintered die 4|, which is then hardened. Where the surfaces and configuration of the die 4| are very fine, this latter process would be desirable to insure against any possible breakage or other destruction to the impression surfaces of the die 4| prior to the sintering and hardening thereof.

In accordance with my process, the mold or templet 38 can also be formed by employing powder metallurgy technique, l. e., by simply placing the original or master die to be re-produced in a press in the manner indicated in Fig. 8 of the drawing, in which case 4| would represent the original die, and 38 would then represent a powdered metal templet die formed from the im- This powdered metal die is then sintered and hardened and used as the templet die in producing the duplicate dies 4|. In this case, a permanent templet die would be formed, from which many of the re-productions 4| could be formed.

It will also be understood that in referring to the die cast templet die 38, these dies when composed of certain types of hard casting materials may be used for producing a number of duplicate die parts therefrom. However, bearing in mind that the templet .die when bodily removed from the re-produced powdered metal die"4| can be re-melted and re-used for the production of a new templet die in a simple die casting process, it is possible to use these die casting templet dies or molds for the production of single powdered metal dies.

It will, of course, be understood that in producing the templet or pattern die part that in addition to producing what might be technically termed the impression surface or cavity of the original dies, the boundary surfaces are also produced. This is also true of the final powdered metal die which must constitute an exact replica of the original die surface as is represented in Fig. 3 or the drawing.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of producing duplicate dies employed for forming die cast products which comprises the steps of first producing a die cast templet die part of the impression surface of an original die part, then using this templet die part in forming a. powdered metal die part having an impression surface corresponding to the impression surface of the original die part, then subjecting the powdered metal die part including the templet die part to a high temperature to sinter the powdered metal. die part and melt the templet die part, and then hardening said sintered powdered metal die part.

. surface of the die part to be produced, then formd s .2. The method of p ative die part of the impression and boundary ing on the negative die part, by the pressure compacting of powdered metal, a powdered metal die part, then sintering and hardening said powdered.

metal die part to form the desired part of the die, and melting the negative die part from the powdered metal die part in the sintering operation.

LOUIS H. MORIN.

oducingdies by powdered. v =metallurgy, which comprises first forming a neg- 

